Passing empty string for route()'s $parameters no longer works

[apih]

Laravel Version

12.6.0

PHP Version

8.2.28

Database Driver & Version

No response

Description

Previously, passing an empty string to route()'s $parameters worked without problem.

Let's say a route is defined like this:

// Affiliate referral link
Route::get('r/{slug}', Controllers\AffiliateLinkController::class)->name('affiliate_link');

When the route is called like this, it works in the previous version, but fails in the latest version:

// v12.3.0 and below
route('affiliate_link', ''); // Will generate 'https://domain.test/r'

// v12.4.0 and above
route('affiliate_link', ''); // Will fail with error message: Missing required parameter for [Route: affiliate_link] [URI: r/{slug}] [Missing parameter: slug].

Probably related to #54811. Ping @stancl .

Steps To Reproduce

• Define a route.

// Affiliate referral link
Route::get('r/{slug}', Controllers\AffiliateLinkController::class)->name('affiliate_link');

• Call the route with an empty string, using route().

route('affiliate_link', '');

[stancl]

Hmm, a lot of the internal code treated '' as missing values, strange. Will fix, thanks for reporting

[stancl]

To clarify, this is a preexisting bug that is made more apparent due to my PR.

if you instead passed ['slug' => ''] in <= v12.3.0 it would fail with the same error. Only passing the empty string positionally worked around this by bypassing the buggy parts of the URL generation logic.

[stancl]

Hmm, it seems according to tests passing an empty string should NOT be allowed.

I was trying to see if a change like this would work:

diff --git a/src/Illuminate/Routing/RouteUrlGenerator.php b/src/Illuminate/Routing/RouteUrlGenerator.php
index c823243634..5a75e8a935 100644
--- a/src/Illuminate/Routing/RouteUrlGenerator.php
+++ b/src/Illuminate/Routing/RouteUrlGenerator.php
@@ -316,7 +316,8 @@ protected function replaceNamedParameters($path, &$parameters)
             } elseif (isset($this->defaultParameters[$m[1]])) {
                 return $this->defaultParameters[$m[1]];
             } elseif (isset($parameters[$m[1]])) {
-                Arr::pull($parameters, $m[1]);
+                // If there's neither a provided value nor a default value, we just use the empty string...
+                return Arr::pull($parameters, $m[1]);
             }

             return $m[0];

That however makes this test fail:

public static function providerRouteParameters()
{
    return [
        [['test' => 123]],
        [['one' => null, 'test' => 123]],
        [['one' => '', 'test' => 123]],
    ];
}

#[DataProvider('providerRouteParameters')]
public function testUrlGenerationForControllersRequiresPassingOfRequiredParameters($parameters)
{
    $this->expectException(UrlGenerationException::class);

    $url = new UrlGenerator(
        $routes = new RouteCollection,
        Request::create('http://www.foo.com:8080/')
    );

    $route = new Route(['GET'], 'foo/{one}/{two?}/{three?}', ['as' => 'foo', function () {
        //
    }]);
    $routes->add($route);

    $this->assertSame('http://www.foo.com:8080/foo?test=123', $url->route('foo', $parameters));
}

But the expectation with which this issue is reported is that passing an empty string (third case in the provider) should work.

What my changes do is turn [''], which apparently unintentionally works, into ['paramName' => ''], which is not allowed according to existing tests.

So I think in your case you should just make the parameter optional.

[apih]

Thanks for your extensive testing @stancl. This issue caught me by surprise in several projects, since several parts relied on this unintended behavior, and works fine before. Based on your explanation, I understand that it was a bug, so moving forward, I will just fix the issue in my projects.